Centrifugal fan

ABSTRACT

A centrifugal fan assembly including a removable orifice ring having tabs thereon, the ring being formed from the material removed in the production of the side plate of the fan housing, the diameter of the orifice ring being substantially equal to the diameter of the opening in the side plate of the fan housing, the tabs on the orifice ring being utilized to locate the orifice ring on the side plate of the fan housing.

United States Patent Cann et al.

[4 1 Oct, 17,1972

[ 54] CENTRIFUGAL FAN [72] Inventors: Peter L. Cann; Richard J. Duell,

both of Syracuse, NY.

[73] Assignee: Carrier Corporation, Syracuse, NY.

[22] Filed: March 31, 1971 [21] Appl. No.: 129,717

[52] US. Cl. ..415/20l, 415/204, 417/363 [51] Int. Cl. ..F04d 1/00, F04d29/40 [58] Field of Search ..415/204, 206, 201, 219 C;

[56] References Cited 7 UNITED STATES PATENTS 3,145,910 8/1964 Jolly417/363 Harris ..417/3 63 3,161,388 12/1964 Appleton ..417l363 3,401,8709/1968 Crowe ..417/363 Primary Examiner-Henry F. Raduazo Attorney-HarryG. Martin, Jr. and J. Raymond Curtin 57 ABSTRACT A centrifugal fanassembly including a removable orifice ring having tabs thereon, thering being formed from the material removed in the production of theside-plate of the fan housing, the diameter of the orilice ring beingsubstantially equal to the diameter of the opening in theside plate ofthe fan housing, the tabs on the orifice ring being utilized to locatethe orifice ring on the side plate of the fan housing.

4 Claims, 5 Dravving Figures PATENTEU BET 17 I973 3.6 98,8 33

5 I INVENTOR.

PETER ANN BY RICHAR ELL ATTORNEY CENTRIFUGAL FAN BACKGROUND OF THEINVENTION Centrifugal fans generally comprise a fan wheel mounted forrotation within a scroll-shaped housing. The housing is provided withcircular inlet openings centered with respect to the fan wheel shaft. Toimprove fan performance, the inlet openings are smaller than the outsidediameter of the fan wheel. To assemble the fan, a portion of one side ofthe fan housing may be removably secured to the housing by bolts orsheet metal screws. Ordinarily, the side of the fan housing is providedwith a circular opening slightly larger than the diameter of the fanwheel. An inlet or orifice ring having an outside diameter greater thanthe diameter of the opening in the housing and an inside diameter equalto the desired inlet opening diameter is placed over the opening in thefan housing and fasteners are inserted through the portion of theorifice ring and the portion of the housing which are in overlappingrelationship to attach the orifice ring to the housing. A plurality offasteners are employed for this purpose. Since the outside diameter ofthe orifice ring is greater than the diameter of the opening in the sideof the fan housing, the orifice ring and the side of the housing must bestamped from separate pieces of sheet metal stock.

SUMMARY OF THE INVENTION This invention relates to a centrifugal fanassembly and a method for manufacturing a fan housing having ascroll-shaped wrapper with first and second side plates secured thereto,the second side plate having a circular opening therein and a pluralityof notches communicating with the circular opening. An orifice platehaving a central circular opening is provided, the plate being formed bythe material removed from the second side plate to provide the circularopening therein, the orifice plate thereby having a diametersubstantially equal to the diameter of the circular opening in thesecond side plate. The orifice plate has tabs formed thereon as a resultof the formation of the notches in the second side plate. The tabs areadapted for engagement with the second side plate at a locationcircumferentially spaced from the notches in the second side plate toposition the orifice plate on the second side plate over the circularopening therein.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a fan housingwith the orifice plate removed therefrom;

' FIG. 2 is an illustration of an orifice plate for use with the fanhousing of FIG. 1;

FIG. 3 is a side view of a fan housing with the orifice plate of FIG. 2placed thereon;

FIG. 4 is a side view of a centrifugal fan assembly with a portionbroken away; and

FIG. 5 is a sectional view taken along line V--V of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring more particularly tothe drawing, there is illustrated a fan housing 3 comprised of ascroll-shaped wrapper 5, a first side plate 7 and a second side plate 9.Side plate 7 is provided with an air inlet opening 8 having a diameterless than the diameter of the fan wheel to be employed in the housing.

Side plate 9 and a,circular orifice plate 11 are provided by blankingorifice plate 11 from side plate 9. Tabs 13 are formed on orifice plate11 which results in notches 15 being formed in side plate 9. Thediameter of opening 17 formed in side plate 9 by the removal of theorifice plate 11 therefrom is therefore substantially equal to thediameter of the orifice plate. An air inlet opening 18 in orifice plate11 and the air inlet opening 8 in side plate 7 are provided for passageof air into the fan housing.

A plurality of depressions 19, corresponding to the number of tabsformed on orifice plate 11, are formed in side plate 9. The depressions19 are circumferentially spaced from notches 15 to receive tabs 13 andposition orifice plate 11 in the plane of side plate 9.

The side plate 9 is preferably formed by first piercing and forming theair inlet opening, 18. The blank is then notched and pierced to providethe approximate exterior shape of the side plate before depressions 19are formed therein and the orifice plate 1 l is blanked out.

The circular opening 17 formed in side plate 9 is sized to allowinsertion of a fan wheel 23 into the completed housing.

The notches 15 provide openings for insertion of resilient grommets 25and bolts 27 to mount a fan motor support bracket 29 on the housing andsecure the orifice plate within opening 17. The motor support bracket,which is adapted to support and position a fan motor 31 and the fanwheel 23 which is secured to the shaft of the fan motor, is providedwith a plurality of arms 37 corresponding to the number of notches inside plate 9.

To mount the motor support bracket and the orifice plate on the fanhousing, the resilient grommets, which have an enlarged headed portion33, a central bore 35 and internally threaded insert 37, are insertedinto the notches in the side plate after the orifice plate is positionedthereon with the tabs aligned with depressions 19. The bolts 27 are theninserted through openings in the motor support bracket arms, threadedinto the grommets 25 and tightened. This causes the grommets to swell onthe inner side of side plate 9 to resiliently secure orifice plate 11and motor support bracket 29 on side plate 9.

It can be seen from the foregoing that a centrifugal fan assembly isprovided which generates a minimum quantity of scrap material in thefabrication thereof and which requires a minimal number of fasteners forassembly. Further, the second side plate including the central opening,depressions and notches and the orifice plate with tabs may be formed bysimple stamping operations. Since the notches are adapted to receive themotor support bracket fasteners, further operations to form openings forfasteners are unnecessary.

While we have described a preferred embodiment of our invention, it isto be'understood that the invention is not limited thereto, since it maybe embodied within the scope of the following claims.

We claim:

1. A centrifugal fan assembly comprising a housing having ascroll-shaped wrapper,

a first side plate associated with said wrapper,

a second side plate having a circular opening therein disposed oppositesaid first side plate on said scroll wrapper, said second side platehaving a plurality of notches formed therein communicating with thecircular opening, I

an orifice plate having a central circular opening therein, said orificeplate comprising material removed from said second side plate to providethe circular opening therein, said orifice plate thereby having adiameter substantially equal to the diameter of the circular opening insaid second side plate, said orifice plate having tabs thereon resultingfrom the formation of the notches in said second side plate, said tabsbeing adapted for en gagement with said second side plate at a locationcircumferentially spaced from the notches in said second side plate toposition said orifice plate on said second side plate over the circularopening therein, and

a fan wheel having an outer diameter larger than said orifice in saidplate and less diameter than the circular opening in said second sideplate mounted for rotation within said housing between said side plates.

2. A centrifugal fan assembly according to claim 1 further includingsupport means for rotatably supporting said fan wheel within saidhousing, and fastening means adapted for cooperation with the notches insaid side plate for securing said support means to said second sideplate.

3. A centrifugal fan assembly according to claim 2 wherein saidfastening means comprise:

a resilient grommet having an enlarged portion on one end thereof,

internally threaded means affixed to the other end of said grommet, saidgrommet being adapted for insertion through the notches in said secondside plate with the other end thereof projecting into said housing, saidenlarged portion engaging the outer surface of said orifice plate andsaid second side plate; and

bolt means adapted for insertion through the center of said grommet forengagement with said threaded means, said bolt being adapted forinsertion through said support means into said grommet, subsequenttightening of said bolt causing the diameter of said resilient grommetinternally of said housing to expand into engagement with said orificeplate and said second side plate to secure said orifice plate and saidsupport means on said second side plate.

4. A centrifugal fan assembly according to claim 3 wherein said firstside plate is provided with an orifice therein for passage of air intosaid housing.

1. A centrifugal fan assembly comprising a housing having ascroll-shaped wrapper, a first side plate associated with said wrapper,a second side plate having a circular opening therein disposed oppositesaid first side plate on said scroll wrapper, said second side platehaving a plurality of notches formed therein communicating with thecircular opening, an orifice plate having a central circular openingtherein, said orifice plate comprising material removed from said secondside plate to provide the circular opening therein, said orifice platethereby having a diameter substantially equal to the diameter of thecircular opening in said second side plate, said orifice plate havingtabs thereon resulting from the formation of the notches in said secondside plate, said tabs being adapted for engagement with said second sideplate at a location circumferentially spaced from the notChes in saidsecond side plate to position said orifice plate on said second sideplate over the circular opening therein, and a fan wheel having an outerdiameter larger than said orifice in said plate and less diameter thanthe circular opening in said second side plate mounted for rotationwithin said housing between said side plates.
 2. A centrifugal fanassembly according to claim 1 further including support means forrotatably supporting said fan wheel within said housing, and fasteningmeans adapted for cooperation with the notches in said side plate forsecuring said support means to said second side plate.
 3. A centrifugalfan assembly according to claim 2 wherein said fastening means comprise:a resilient grommet having an enlarged portion on one end thereof,internally threaded means affixed to the other end of said grommet, saidgrommet being adapted for insertion through the notches in said secondside plate with the other end thereof projecting into said housing, saidenlarged portion engaging the outer surface of said orifice plate andsaid second side plate; and bolt means adapted for insertion through thecenter of said grommet for engagement with said threaded means, saidbolt being adapted for insertion through said support means into saidgrommet, subsequent tightening of said bolt causing the diameter of saidresilient grommet internally of said housing to expand into engagementwith said orifice plate and said second side plate to secure saidorifice plate and said support means on said second side plate.
 4. Acentrifugal fan assembly according to claim 3 wherein said first sideplate is provided with an orifice therein for passage of air into saidhousing.